The present invention relates to an apparatus for drilling holes, and more particularly, for drilling dowel holes for joining one workpiece to another using, for example, dowels, and for drilling pocket holes for fastening one workpiece to another using, for example, screws.
Traditionally, the drilling of dowel holes and pocket holes has been accomplished with either a jig or a large piece of machinery. The jig, while economical, is time-consuming to set up and use, and often lacks accuracy. Large machinery is suitable for large production job shops but is too expensive and too bulky for a carpenter, a small job shop, or a do-it-yourself woodworker. The invention disclosed addresses the needs of, although not limited to, the carpenter, small job shop, or do-it-yourself woodworker.
Dowel joinery is a very old process and some attempts have been made to mechanize the creation of the dowel hole with limited success. One example of a jig to hold the workpiece appears in U.S. Pat. No. 4,594,032. This jig clamps to the workpiece, possibly causing damage to softer woods, and allows for a very limited number of dowel sizes and workpiece thicknesses. Another example of a jig that holds the workpiece and a powered drill appears in U.S. Pat. No. 4,235,565. This jig is time-consuming to set up for each change of workpiece thickness and requires that it be attached to a bench or table before using it. The present invention does not clamp to the workpiece, so has little chance of damaging it, will support any standard or custom size dowel up to about one inch in diameter, and any workpiece thickness. The present invention is hand-held and portable, so it is easily moved from one drilling operation to the next.
Pocket-hole joinery is a more recent process (reference U.S. Pat. No. 3,496,974) and the jigs developed have mirrored those of the dowel joinery process. One example of a jig to guide a stepped drill bit appears in U.S Pat. No. 5,781,835. The workpiece is clamped in the jig, which can possibly damage the workpiece, the thickness of the workpiece is limited, and it is awkward to use with large workpieces. An example of a powered tool that mechanizes part of the process appears in U.S. Pat. No. 5,375,636. It is a semi-production machine that, in the preferred embodiment, is meant to be mounted to a bench or table. It addresses many of the drawbacks of a jig, but still requires a separate powered hand drill to make the pilot hole cut. The present invention does not clamp to the workpiece, so has little chance of damaging it, and will handle workpieces from about one-half inch to about one and one-half inches thick. The preferred embodiment of the present invention cuts both the bore and pilot hole in one operation and doesn""t require any additional steps or equipment to cut a pocket hole.
There is prior art for jigs that guide a drill bit and jigs that guide a portable hand drill, but a dedicated, hand-held, portable, powered drill for creating dowel holes does not currently exist. Similarly, there is prior art for jigs that guide a stepped, pocket-hole drill bit and large, production-sized machines for creating pocket holes, but a dedicated, hand-held,, portable, powered drill for creating pocket holes does not currently exist. The present invention performs the task of drilling both dowel holes and pocket holes and provides the accuracy, versatility, and convenience of use that users desire.
The idea for the present invention came about after building a slatted table top with breadboard ends. The slats were narrow, so each slat had to be joined to the breadboard ends with a dowel joint. The holes for the dowels had to be precisely placed so that all of the workpieces were coplanar once the joints were assembled. This required the use of a doweling jig. The jig was supposed to clamp to the end of the board and guide the drill bit, but because the slats were so narrow, the jig kept slipping off the workpiece making the dowel holes difficult to cut. I envisioned a device somewhat similar to a biscuit cutter or plate jointer, as disclosed in U.S. Pat. No. 4,913,204 to Moores et al., such that a fence would be used to position the device to the workpiece and a plunging motion of the motor and drill bit with respect to the base and fence assembly would produce an accurate dowel hole. However, such a dedicated device would not be economically feasible.
Another project brought up the need to join several workpieces together using a pocket-hole joint. Again, this required a jig to hold the workpiece while the user drilled pocket holes in the workpiece. The choices were either inexpensive jigs that required a lot of setup for each pocket hole, or a relatively expensive jig that reduced the setup time somewhat. Both had the same drawback, as does the doweling jig, that the jig needed to be clamped to the workpiece, which can mar softwoods.
The solution was to take my original idea and give it the ability to drill oblique holes for pocket-hole joints. This device would be able to drill dowel holes quickly, accurately and with very little setup time and, by tilting the motor and drill bit assembly with respect to the base, would be able to drill pocket holes quickly, accurately and with very little setup time. Since my upper and lower fences rest against the workpiece without gripping, to cut either type of hole, it can""t mar softwoods. My dual-purpose device is easy to move around the workshop, the workpiece can be brought to the device to cut the holes, or the device can be brought to the workpiece whether it""s on the bench or at the work site. This combination dowel hole and pocket hole drill would be economically feasible.
Marring of softwood workpieces also can be produced by hold-down devices. Mastley patent, 6,374,878, utilizes such hold-down members that are xe2x80x9cpressed against the workpiece to keep the workpiece from moving upward.xe2x80x9d (upon retraction of the drill after the hole is formed); see col. 3, lines 50-60. Such members can make undesirable indentations in soft woods, like the aforesaid gripping action. While Raines 4,842,453 does not require a workpiece clamp or mar producing hold-down device pushing against the softwood workpiece, the fixture holding the workpiece has to be held down to keep it from moving about during the drilling operation. The need to hold the fixture against a support table is eliminated by the present invention. Also, the support table 40 of Raines tilts back to accommodate thicker workpieces. Ideally, the angle of the workpiece to the pocket-hole drill bit should be around 15 degrees. By tilting the support table 40 back, the angle of the workpiece to the drill bit increases substantially. This increases the difficulty in keeping the two workpieces coplanar during assembly. This device was meant to work primarily with xc2xe inch thick workpieces.
The present invention provides a single apparatus enabling a user to drill accurate, repeatable dowel holes in an expeditious manner. Further, the present invention provides the ability to drill accurate, repeatable pocket holes in an expeditious manner with such a single apparatus without the need for the user to perform tedious, time consuming, error prone calculations.
An object of the present invention is to provide a portable hand-held drilling machine that is easily carried from place to place by the operator.
Another object of the present invention is to provide a simple and quick means to create a dowel-hole joint that can be secured with a wooden dowel.
Another object of the present invention is to provide a first fence for the purpose of accurate alignment and placement of the tool to the workpiece prior to drilling the dowel hole. A further object of the present invention is to provide an accurate graduated indicator for proper placement of the fence prior to drilling the dowel hole.
Another object of the present invention is to provide a simple and quick means to create a pocket-hole joint in addition to the dowel joint that can be secured with a mechanical fastener.
Another object of the present invention is to provide a second fence for the purpose of accurate alignment and placement of the tool to the workpiece prior to drilling the pocket hole. A further object of the present invention is to provide special scale markings to indicate proper placement of the second fence prior to drilling the pocket hole.
Another object of the present invention is to provide a means to restrict the location of the supporting structure in relation to the base and fence system with a repositionable device intended to physically abut the supporting structure. A further object of the present invention is to provide special scale markings to indicate proper placement of the repositionable device prior to drilling dowel holes or pocket holes.
Another object of the present invention is to provide a structure to support and rotate a drilling bit and to move that structure axially to the tool and in relation to the base and fence system.
Another object of the present invention is to provide a means to pivot the supporting structure in relation to the base and fence system to rapidly and easily accommodate the angle of the tool to the workpiece required for either a dowel-hole drilling operation or a pocket-hole drilling operation. A further object of the present invention is to provide structure to designate to the operator the proper angle of the pivotable supporting structure.
Another object of the present invention is to provide a machine with a tool-guiding jig to eliminate vertical and lateral movement of the tool during operation.
The currently most preferred apparatus embodying the invention, see FIG. 14, has a motorized drill 30 slidably coupled to a pivotable support platform 26 and movable along the platform for drilling a hole in a workpiece 108, the support platform being pivotably coupled to a base assembly. An adjustable travel limiting stop arrangement 28, 32, 36, after being manually set by the user automatically limits the degree of drill travel and hence the depth of the holes drilled. A clamping arrangement 54, 56, 58, FIG. 2, enables the user to selectively maintain the motorized drill parallel with respect to the base assembly 44 for drilling dowel holes or alternatively, for maintaining the drill at an appropriate angle that is about fifteen degrees with respect to the base for drilling pocket holes as indicated in FIGS. 1c and 1d. 
For forming pocket-holes, a horizontally movable pocket hole workpiece positioning fence 66, FIG. 14, contacts at its inside surface a front side of the workpiece and holds it against the lower portion of the base assembly 44, and a pocket-hole depth establishing device includes a first manually adjustable workpiece thickness scale and pointer along with a second manually adjustable workpiece thickness scale and pointer. The first scale 42 and pointer, FIG. 10, is manually set by the user to the workpiece thickness to establish the proper depth of the pocket hole and the second scale 90 and pointer is also set by the user to the workpiece thickness to establish the proper position of entry of the drill near an edge portion of a workpiece (FIGS. 1c, 1d, and 14). Thus, if thin workpieces are to be joined, the drill entry will be close to the workpiece edge and the hole depth will be short to prevent a screw fastener from going all the way through the second workpiece, and conversely, if relatively thick workpieces are to be joined, the drill entry point will be further away from the workpiece edge and the hole depth will be much longer to accommodate a longer screw fastener. As a result, an adjustable pocket-hole parameter input mechanism is provided for drilling different sizes of pocket holes without the need for tedious, time consuming, error prone user calculations.
Additionally a vertically adjustable dowel-hole workpiece positioning fence 60, FIG. 7, is slidably coupled to the base assembly and clamped thereto, for precisely positioning the workpiece with respect to the movable drill, for proper location of dowel-holes within the workpiece.
Also, the support platform coupling device 46, 48, FIG. 11, is configured to quickly and easily uncouple the support platform from the base assembly when a pivot angle therebetween exceeds a predetermined value, for cleaning and maintenance of the drilling apparatus components.